Photographic printing element containing fluorescent dye

ABSTRACT

A PHOTOGRAPHIC PRINTING ELEMENT CONTAINING A WATERSOLUBLE FLUORESCENT WHITENING DYE AND A WATER-SOLUBLE POLYMER OF AN N-VINYLAMIDE COMPOUND.

y 1972 NOBUO TSUJI ETAL 3,666,470

PHOTOGRAPIIIC PRINTING ELEMENT CONTAINING FLUORESCENT DYE Filed July 5,1969 RELATIVE NNUJ 4 UT 9? bi 5 I Z 24 WATER WASHING TIME INVENTORSNOBUO TSUJI, TATSUYA TAJIMA TAKUSHI MIYAZAKO, YOSHINORI TSUCHIYAFUMIHIKO NISHIO ATTORNEYS United States Patent 3,666,470 PHOTOGRAPHICPRINTING ELEMENT CONTAINING FLUORESCENT DYE Nobuo Tsuji, Tatsuya Tajima,Takushi Miyazako, Yoslunori Tsuchiya, and Fumihiko Nishio, Kanagawa,Japan, assignors to Fuji Photo Film Co., Ltd., Ashigara-Kamigun,Kanagawa, Japan Filed July 3, 1969, Ser. No. 838,812 Claims priority,application Japan, July 4, 1968, 43/ 46,708 Int. Cl. G03c 1/92 US. Cl.96-82 9 Claims ABSTRACT OF THE DISCLOSURE A photographic printingelementcontaining a watersoluble fluorescent whitening dye and a water-solublepolymer of an N-vinylamide compound.

The present invention relates to a photographic printing element and inparticular to a photographic printing element having improved whitenessin the absence of a matt surface.

Hitherto, in order to improve the whiteness of nonimage (blank) portionsof a printed photographic printing element, it has been attempted toincorporate a fluorescent whitening dye, which emits a purple or a bluefluorescence by absorbing ultraviolet rays, in photographic layers, suchas a baryta layer, an undercoating, a light-sensitive emulsion layer, aprotective layer applied to a support or an image receiving layer of aprinting element for diffusion transfer photography (hereinafter, theselayers are called photographic layers). Water-soluble polyvinylpyrrolidone in one of these photographic layers, and watersolublepoly-N-vinyl-S-methyl-2-oxazolidinone have also been incorporated in oneof these layers for this purpose.

However, the conventional method of incorporating a fluorescentwhitening dye has the drawback that, since the fluorescent whitening dyeis not absorbed on the colloidal component of photographic layers, suchas gelatin, although the fluorescent dye has a direct dyeing afiinity tofibers, the intensity of fluorescence emitted from the fluorescentwhitening agent incorporated in photographic layers is weaker than thecase where the same fluorescent dye is absorbed on fibers, andsuflicient whitening effect is not obtained. Furthermore, the greaterpart of the fluorescent whitening dye present in the photographic layeris removed in the water-washing stage after development, which severelyweakens the whitening effect.

The aforesaid method of incorporating water-solublepoly-N-vinyl-S-methyl-Z-oxazolidine or water-soluble polyvinylpyrrolidone in the photographic layer has the drawback that, althoughthe whitening effect is higher as the degree of polymerization of thepolymer to be employed is higher, when a polymer having a high degree ofpolymerization is employed, the surface of the photographic printingelement is matted.

Therefore, an object of the present invention is to pro* vide aphotographic printing element having improved whiteness by employing awater-soluble fluorescent whitening dye without the accompaniment of theaforesaid drawbacks.

Another object of the present invention is to provide a water-solublehigh molecular weight compound to be employed together with afluorescent'whitening dye for improving the whiteness of a photographicprinting element by being incorporated in a photographic layer of theelement without being accompanied by the aforesaid drawbacks.

We have found that the above objects can be achieved by theincorporation of a fluorescent whitening dye and a water-soluble highmolecular weight compound, which compound is prepared by polymerizing anN-vinylamide compound represented by the formula CH =CHNR COR wherein Rrepresents methyl or ethyl and R represents hydrogen, methyl or ethyl,or copolymerizing the above monomer with another comonomer, in at leastone of the photographic layers of a photographic printing element, suchas, a baryta layer, an undercoating, a light-sensitive emulsion layer, aprotective layer, or a diffusion transfer imagereceiving layer appliedon a support.

The water-soluble fluorescent whitening dye (or fluorescent brighteningagent) to be employed in the present invention is one which emits ablue-purple fluorescence (of wavelengths of 43 0-470 mu.) by absorbingultraviolet rays. As fluorescent whitening dyes which may be employed inthe present invention, there may be mentioned those known water-solublefluorescent dyes having a direct dyeing aflinity, such asdiaminostilbene dyes, benzidine dyes, triazole dyes, imidazole dyes, andimidazolone dyes. Specific examples of such fluorescent whitening'dyesare as follows:

Diaminostilbene fluorescent dyes (a) Compounds of the formulaQCEECH-QNHQIE] wherein X, Y, X, and Y each represents -NHC H --NHC H SONa, 0H, NH NHCH CH SO Na, --OCH CH OH, or -OC,H and n. represents 5 to100.

CdHgNHCONH NHCONHC|H 1 SOaNa SOaNa n wherein n represents 5 to 100.

Benzidine fluorescent dyes (a) Compounds of the formula SOaNa SOaNawherein R and R' each represents H, -CH or OCH (b) Compounds of theformula wherein R represents H, -CH OCH Triazole fluorescent dyes N iNaS'OaNa N s SOINB (b) N R and R each represents a hydrogen atom, an alkylor Naoas hydroxyalkyl group having 1-12 carbon atoms, a sulo- N CH=OHQalkyl group (or an alkali metalsalt or ammonium salt thereof), acanboalkyl group (or an alkali metal oram 503m, monium salt thereof), anaralkyl group, an aryl group having 6-18 carbon atoms," a hydroxycarboxyor sulfonic acid derivative of the aryl group, or an, alkali metal or(6) ammonium salt of the aryl group, a cycloalkylgroup having 6-10carbon atoms, or a substituted cycloalkyl group;

A represents an alkylene group having 4-5 carbonatoms Compounds of theformula or an alkylene group having a hetero atom or hetero N N atomicgroup; Y represents an alkylene group having 2-10 carbon atoms, asubstituted alkylene group, an alkylene C @343; group having 6-18 carbonatoms, or a substituted alkylene group; Z represents adivalent heteroarmor. atomic s Q Na S osNa B group; m is 0 or 1; and M represents analkali metal'or aml monium group. a v

z (7) These fluorescent whitening dyes which may be em ployed in thepresent invention are well-known to those wherein R represents H, CH C HOCH 0 skilled in the art and are readily commercially available -SO Naand R represents H, CH or by the trade names of Blankophor(Farbenfabriken' Imidazole fluorescent dyes Bayer A. G.), Leucophor(Geigy Chemical CorpJ, CHZCHZOH Tinopal (Sandoz A. G.), Uvitex(Ciba'Ltd.),'"Kaya-' Imidazolone fluorescent dye phor (Nippon Kayaku K.K.), Potamin White .(Dupont), Whitex (Sumitomo Chemical IndustriesCoJ',and (Honshu Chemical Co.). Forexample, Blanl 6 NE NH ophor B is afluorescent whitening agent corresponding to S We Formula 1 andBlankophor R corresponds to Formula 2. i f i A (3) 40 The Water-solublehigh molecular weight compound The above dye is disclosed in applicantsJapanese patent used in this invention may be either a homopolymer of anapplication No. 22,756/ 67. N-vinyl amide represented by the generalformula High molecular weight compounds having at least one ofCH2=CHNR1CoR2 7 V the repeating units represented by general Formulas 7W (9) and (10) or a copolymer of such N-vinylamide and-another tno'nCompounds of the formula omer such as acry1am ide,'methacry1amide,'N-methylacryl wherein R and R each represents a hydrogen atom, anamide, N,N-dimethylacrylamide, N,N- diethylacrylamide, alkyl grouphaving 1-3 carbon atoms, an aryl group havacryloyl morpholine,N-methylolacrylafiiide; N hyiiroxy ing 6-42 carbon atoms, a.hydroxyalkyl group having 2-4 ethylacrylamide, acrylic acid, methacrylicacid; methyl carbon atoms, a substituted hydroxyalkyl groupfasulfoacrylate, hydroxethyl 'acrylate, acrylonitrile', l-vinyl-Q alkylgroup having 1-4 carbon 3101115, an alkali metal salt methyl'm idazole,N-vinylpyriding, 4-viny1pyridine; N- thereof, or an ammonium salt; Rrepresents a halogen vinylpyn'olidone, N m l l idi i i g ql atom, CR,SR, I tam, N-vinyl-5-methyl-2-oxazolidinone, vinyl acetate,

if maleic anhydride, sodium 'p-vinylberizenefsulfonate,or

. R i methyl vinyl ether. V I I x The aforesaid N-vinylamide:compoundrepresented by 35 the above general formula may be easilyprepared by IQ? acting the corresponding N-alkylacyl compoundrepresented by the general formula R CONHR and acetylene in an autoclavein the presence of an alkali catalyst.

As examples of the N-vinylamide compound, there may be mentionedN-vinyl-N-methylformamide (boiling point 73 C. at a pressure of 50 mm.Hg), N-vinyl-N- methyl acetamide (boiling point 63 C./ 17 mm. Hg), N-vinyl-N-methylpropionamide (boiling point 75 C./ 17 mm. Hg),N-vinyl-N-ethylformamide (boiling point 81 C./50 mm. Hg), and the like.

The desired polymer may be obtained by dissolving the above N-vinylamidecompound in a solvent such as water, an alcohol, benzene, ligroin or thelike and conducting the polymerization in a nitrogen gas stream at atemperature of about 40-100 C. in the presence of a catalyst such ashydrogen peroxide, potassium persulfate, 2,2-azobisbutyronitrile, or thelike.

In the case of preparing the copolymer of this invention, it ispreferable for improving the whitening effect that the proportion of theaforesaid comonomer be less than 20 mole percent of the total amount ofcopolymer.

In order to obtain the desired whitening effect, higher molecular weightpolymers are desirable for use in the present invention, and themolecular weight is preferably in the range of about 50,000500,000(intrinsic viscosity 0.2-1.5 in an aqueous solution at 30 C.).Particularly useful are polymers having a molecular weight of about100,000400,000 (intrinsic viscosity 0.5-1.2 in an aqueous solution at 30C.). However, polymers possessing molecular weights above and belowthese ranges may be employed.

When using the aforesaid conventional N-vinylpyrrolidone polymer, if themolecular weight thereof is higher than 100,000, and particularly if itapproaches about 360,000, the miscibility of the polymer with gelatin isdegraded, whereby the surface of the photographic printing paper tendsto be severely matted. On the other hand, the aforesaid N-vinylamidepolymer of this invention having a molecular weight of higher than100,000 shows a good miscibility with gelatin and moreover even if themolecular weight thereof is over 300,000, very little lack ofmiscibility occurs, provided the amount of the polymer employed is notexcessive, that is, not more than about 60% by weight.

There exists no particular limitation on the amount of of theN-vinylamide polymer or copolymer of the present invention providedsufficient polymer is present to obtain the desired whitening effect. Ingeneral, at least by weight of the polymer based upon the total weightof polymer and gelatin binder is desirable to obtain significantwhitening eifect. However, since the use of an excess amount of thepolymer does not substantially increase the whitening effect over avalue achieved by about 40% by weight, and in fact reduces miscibilitywith gelatin and causes a degradation of the quality of the image and isin addition uneconomical, the preferred amount of polymer employed isabout 5-40% by weight. Most preferably, the amount employed is about15-25% by weight.

As mentioned above, the photographic layers of the photographic printingelement of this invention include any of a silver halide emulsion layer,a baryta layer, an undercoating, a protective layer applied to a supportsuch as paper, synthetic resin film, a glass plate or a metal plate andan image receiving layer for a diffusion transfer printing elementapplied to the support. The fluorescent whitening dye and thewater-soluble high molecular weight compound may be incorporated in anyone of the above photographic layers to provide the desired effect.Further, the water-soluble high molecular weight material may beincorporated in a different photographic layer than the layer containingthe fluorescent whitening dye.

Also, the invention has been exemplified above in terms of using gelatinas the binder. However, other binders such as synthetic resins may besimilarly employed in the present invention.

By the present invention, a photographic printing element providing thesame or a superior effect than con ventional photographic elementscontaining an N-vinylpyrrolidone polymer or anN-vinyl-S-methyloxazolidione polymer is provided without resulting inthe matting of the surface encountered in the conventional methods.

The invention will be explained more practically based on the followingexamples.

EXAMPLE I To a gelatino silver halide emulsion containing 50 g. ofgelatin and 20 g. of silver chlorobromide (containing 30 mole percentsilver bromide) were added 0.5 g. of the fluorescent whitening agentBlankophor BUP (trade name of Farbenfabriken Bayer A. G.) and 10 g. ofan N vinyl N methylacetamide homopolymer having an intrinsic viscosityof 1.05, 0.58, or 0.32 in an aqueous solution of 300 C. Then, afteradding to the emulsion formaldehyde as a hardening agent and saponin asa wetting agent, the resulting silver halide emulsion was applied to aphotographic baryta paper of g./sq. meter to provide a photographicpaper. The photographic paper thus prepared was processed in a developerand a fixing solution having the following compositions respectively;

Developer: G. Metol (p-methylaminophenol sulfate) 1.0 Sodium sulfite(anhydrous) l5 Hydroquinone 4 Water to make, 1 liter.

The sample was washed with running water of 15 C. for 1, 5, or 24 hours.

The photographic paper thus prepared and processed was tested forintensity of fluorescence, the results of which are shown in the figureof the accompanying drawing. In the figure, there is shown the relationbetween the water-Washing time and the relative intensity offluorescence, which was a relative value when the whiteness of thesurface of the photographic paper itself was assumed to be 25. In thefigure, curve 1 stands for the results in the case of using the highmolecular weight compound having an intrinsic viscosity of 1.05, curve 2for the case of using the high molecular weight compound having anintrinsic viscosity of 0.58, and curve 3 for the case of using the highmolecular weight compound of an intrinsic viscosity of 0.32. Curve (a)in the figure represents a con trol run, using a paper prepared asabove, but having incorporated therein only the fluorescent whiteningdye and not the water-soluble high molecular weight compound.

As will be understood from the results shown in the figure, theintensity of fluorescence of the photographic papers of this inventionwas remarkably higher than the result of the control sample shown bycurve (a) and among the photographic papers of this invention, thesample having the water-soluble high molecular Weight material having ahigher molecular weight gave higher intensity of fluorescence. Moreover,even though the watersoluble high molecular weight compound having ahigher molecular weight was employed, the surface properties of thephotographic paper were not injured. Also, very little reduction inwhiteness by water washing was observed.

EXAMPLE II To one liter of a baryta coating dispersion having thefollowing composition were added one gram of Blankophor EU? as thefluorescent whitening dye and g. of an N-vinylsN-methylformamide polymerhaving an intrinsic viscosity of 1.05 (molecular weight of 40,000):

Water to make, 1 liter.

The baryta coating composition was applied to a paper in a thickness of100 g./ sq. meter. To the baryta coated paper was applied a gelatinosilver halide emulsion containing 50 g. of gelatin and 20 g. of silverchloride and having added thereto formaldehyde as a hardening agent andsaponin as a wetting agent followed by drying.

The photographic paper thus prepared was processed as in Example I andthe result was compared with a control paper wherein no-N-vinyl-N-methylformamide polymer was incorporated in the baryta layer.The results showed that the whiteness of the surface of the photographicpaper of this invention was much better than the control case. Moreover,the whitetness of the photographic paper of this invention was notreduced by water washing.

EXAMPLE HI After adding formaldehyde as a hardening agent and saponin asa wetting agent to a gelatino silver halide emulsion containing 20 g. ofsilver chlorobromide (60 mole percent silver bromide) per 50 g. ofgelatin, the resulting silver halide emulsion was applied to a barytacoated paper of 150 g./sq. Before drying the silver halide emulsionlayer, an aqueous solution containing 0.7 g. of Whitex BF (trade name ofSumitomo Chemical Industries Co.) as a fluorescent whitening dye, 8 g.of the N-vinyl-N-methylformamide having an intrinsic viscosity of 0.90,3 ml. of formalin, 6 ml. of a 6% methanol solution of saponin, and oneliter of Water was applied to the silver halide emulsion layer in asetting state and dried. The photographic paper thus prepared wasprocessed and dried as in Example I and the results were compared with acontrol paper having no N-vinyl-CN-methylformamide polymer added. Theresults showed that the whiteness of the surface of the photographicpaper of this invention was higher than the control case. Also, thewhiteness of the photographic paper of this invention was not reduced bywater washing.

EXAMPLE 1V After adding 0.5 g. of Kayaphor S (trade name of NipponKayaku K. K.) as a fluorescent whitening agent and formaldehyde as ahardening agent and saponin as a wetting agent to a gelatino silverhalide emulsion containing 20 g. of silver iodobromide (1.5 mole percentsilver iodide) to 50 g. of gelatin, the resulting emulsion was appliedto a baryta coated paper of 150 g./ sq. meter. To the silver halideemulsion layer in a setting state before drying was applied an aqueoussolution containing 20 g. of gelatin, 8 g. of theN-vinyl-N-methylpropionamide polymer having an intrinsic viscosity of0.98, 3 ml. of an aqueous 30% solution of formalin, 6 ml. of a 6%methanol solution of saponin, and one liter of water followed by dryingto provide a protective layer.

The photographic paper thus prepared was processed and dried as inExample I and the results were compared with a control having no addedN-vinyl-methylpropionamide polymer in the protective layer. The resultsshowed that the whiteness of the surface of the photographic paper ofthe present invention was much better than'in the control. Moreover, thewhiteness was not reduced by water washing after processing.

EXAMPLE V To the baryta coating composition as shown in Ex ample II wasadded 12 g. of an N-vinyl-N-methylformamide polymer having an intrinsicviscosity of 0.85 and the resulting composition was applied to a paperof ,100 g./sq. meter followed by drying. To the baryta layer was applieda gelatino silver halide emulsion containing 20 g. of silverchlorobromide (30 mole percent silver bromide) to 50 g. of gelatin. andhaving added thereto formaldehyde as a hardening agent and saponin as awetting agent. Further. to the silver halide emulsion layer in a settingstate before drying was applied an aqueous solution containing 20 g. ofgelatin, 1 g. of the benzidine fluorescent whitening dye of the formula(3H H V 0 (FBI QQ S0 Na -SOaNa 3 ml. of an aqueous 30% solution offormalin, 6 mil of a 6% alcohol solution of saponin, and one liter ofwater followed by drying.

The photographic paper thus prepared was processed and dried as inExample I and the results were compared with a control having no addedN-vinyl-tN-methylform amide polymer. The whiteness of the photographicpaper of this invention was much better than the control and also wasnot reduced by water washing after processing.

EXAMPLEVI After adding to one liter of the baryta coating composition asshown in Example H one gram of the imidazolone fluorescent whitening dyerepresented by the formula as the fluorescent whitening agent, theresulting composition was applied to a paper of 100 g./s'q. meterfollowed by drying. Thereafter, a gelatino silver'halide emulsioncontaining 20 g. of silver iodobromide (1.5 mole percent silver iodide)to 50 g. of gelatin having added thereto 12 g. of a copolymer having :amole ratio of N-vinyl-N-methylacetamide to acrylamide of 9:1 and anintrinsic viscosity of 0.85, formaldehyde as a hardening agent, andsaponin as a wetting agent was applied to the baryta layerfollowedbydrying. I

The photographic paper thus prepared was processed and dried as inExample I and the results were compared with a control wherein theaforesaidc'opolymer was not incorporated in the emulsionflayenTheresults showed that the whiteness of the surface of the photographicpaper of this invention was much better than the "control case and wasnot reduced by water washing after processmg. p

EXAMPLE VII To one liter of a aqueous 5% gelatin solution containingcolloidal nickel sulfite were aded 0.5 g. of .Tinopal G (trade name ofSandoz A. G.) as a fluorescent whitening dye and 1 2 g. of a copolymerhayinga mole ratio of N-vinyl-N-methylformamide "to methacrylamide of9:1 and an intrinsic viscosity of 0:75 andthe' resulting solution wasapplied to a paper of g. /sq. meter. On the layer thus formed wasapplied a stripping layermainly consisting of sodium alginate, to'provide a diifusion transfer image receiving element.

The image receiving element thus prepared was closely placed on alight-sensitive layer having a silver halide emulsion layer which hadbeen exposed. The assembly was passed through a diffusion transferringdeviceand a developer and the image receiving element was stripped fromthe light-sensitive elemen't after- 30 seconds; The results werecompared with 'a control wherein the aforesaid copolymer was notemployed. The results showed that the whiteness of the white background.portions of the positive image was better than the control. v

9 EXAMPLE VIII To a gelatino silver halide emulsion containing 20 g. ofsilver chlorobromide (30 mole percent silver bormide) to 50 g. ofgelatin was added 10 g. of an N-vinyl-N-methylacetamide polymer havingan intrinsic viscosity of 1.05 and the resulting silver halide emulsionwas, after the addition of formaldehyde as a hardening agent and saponinas a wetting agent, applied to a baryta coated paper of 150 g./sq.meter. The photographic layer was developed in the developer of ExampleI, but having added thereto 0.7 g./liter of Blankophor BUP and thenfixed, washed with water and dried as in Example I. The results werecompared with a control where no N- vinyl-methylacetamide polymer wasadded to the silver halide emulsion layer. The whiteness of the surfaceof the photographic paper of this invention was better than the controland was not reduced by water after processing.

What is claimed is:

1. A photographic printing element having photographic layers, at leastone of said photographic layers containing a water-soluble fluorescentwhitening dye and a water-soluble member selected from the groupconsisting of a polymer and a copolymer of a compound represented by theformula CH2=CH wherein R represents a radical selected from the groupconsisting of methyl and ethyl and R represents a radical selected fromthe group consisting of hydrogen, methyl and ethyl.

2. The photographic printing element as claimed in claim 1 wherein saidwater-soluble fluorescent whitening dye is selected from the groupconsisting of a diaminostilbene fluorescent dye, a benzidine fluorescentdye, a triazole fluorescent dye, an imidazole fluorescent dye and animidazolone fluorescent dye.

3. The photographic printing element as claimed in claim 1 wherein saidcompound is selected from the group consisting ofN-vinyl-N-methylformamide, N-vinyl-N- methylacetamide, N-vinylN-methylpropionamide, and N vinyl-N-ethylformamide.

4. The photographic printing element as claimed in claim 1 wherein saidphotographic layer is selected from the group consisting of a barytalayer, an undercoating layer, a light-sensitive silver halide emulsionlayer and a protective layer.

5. The photographic printing element as claimed in claim 1 wherein saidphotographic layer is a diffusion transfer image receiving layer.

6. A photographic printing element as claimed in claim 1 wherein saidmember is a homopolymer.

7. A photographic printing element as claimed in claim 1 wherein saidmember is a copolymer of said compound and another vinyl monomer.

8. A photographic printing element as claimed in claim 1 wherein thewater-soluble fluorescent dye and the watersoluble member selected fromsaid group are in different photographic layers of said element.

9. A photographic printing element as claimed in claim 1 wherein saidwater-soluble member has a molecular weight of about 50,000-500,000.

References Cited UNITED STATES PATENTS 3,269,840 8/1966 Pattyn et al.9682 FOREIGN PATENTS 22,065 7/1964 Japan 95-82 245,729 7/1967 Germany9682 M RONALD H. SMITH, Primary Examiner U.S. Cl. X.R.

96-85, 87 R, 76 R, 114; 11733.'5 T

